Removal of raffinose galactooligosaccharides from lentil (lens culinaris med.) by the Mortierella vinacea IBT-3 α-galactosidase

The efficiency of the α-galactosidase from Mortierella vinacea IBT-3 in reducing raffinose and stachyose content in lentil flour was studied and compared with traditional processing. The enzyme was most active at 50°C and pH 4.0–5.0. Its specific activity was 20.5 U mg −1 . The α-galactosidase was stable at neutral and alkaline pH. It was stable for 1 hour at 50°C but it lost 56% of the initial activity after 1 hour at 60°C. The optimal conditions for removal of raffinose and stachyose were: pH 5.0, 50°C, 1 hour, 15% (w/v) suspension of lentil flour and 0.85 U g −1 of lentil flour. The enzyme almost completely removed raffinose family sugars from lentil flour, whereas its cooking for 1 hour at 100°C diminished raffinose and stachyose contents by 78 and 85%, respectively. Concentrations of these sugars were also decreased by autoclaving (121°C, 30 min.) by 15 and 29%, respectively.